doc-tests don't work with macros 1.1

[colin-kiegel]

It looks like having proc-macro = true in Cargo.toml disables all doc-tests. However unit tests #[test] work fine.

Steps to reproduce

1. cargo new foo

2. edit Cargo.toml

# ... the usual
[lib]
proc-macro = true

3. edit src/lib.rs

//! ```rust
//! fn main() { panic!() } /* <-- this test should fail */
//! ```

#![crate_type = "proc-macro"]
extern crate proc_macro;

#[proc_macro_derive(Foo)]
pub fn derive(_: proc_macro::TokenStream) -> proc_macro::TokenStream {
    unimplemented!()
}

4. cargo test

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured